i_block.c revision a6ce1349539f866334ef3d5758bc2ee44a454acd 
1/*
2 * i_block.c --- Manage the i_block field for i_blocks
3 *
4 * Copyright (C) 2008 Theodore Ts'o.
5 *
6 * %Begin-Header%
7 * This file may be redistributed under the terms of the GNU Library
8 * General Public License, version 2.
9 * %End-Header%
10 */
11
12#include <stdio.h>
13#if HAVE_UNISTD_H
14#include <unistd.h>
15#endif
16#include <time.h>
17#include <string.h>
18#if HAVE_SYS_STAT_H
19#include <sys/stat.h>
20#endif
21#if HAVE_SYS_TYPES_H
22#include <sys/types.h>
23#endif
24#include <errno.h>
25
26#include "ext2_fs.h"
27#include "ext2fs.h"
28
29errcode_t ext2fs_iblk_add_blocks(ext2_filsys fs, struct ext2_inode *inode,
30				 blk64_t num_blocks)
31{
32	unsigned long long b = inode->i_blocks;
33
34	if (!(fs->super->s_feature_ro_compat &
35	      EXT4_FEATURE_RO_COMPAT_HUGE_FILE) ||
36	    !(inode->i_flags & EXT4_HUGE_FILE_FL))
37	    num_blocks *= fs->blocksize / 512;
38
39	b += num_blocks;
40
41	if (fs->super->s_feature_ro_compat &
42	    EXT4_FEATURE_RO_COMPAT_HUGE_FILE) {
43		b += ((long long) inode->osd2.linux2.l_i_blocks_hi) << 32;
44		inode->osd2.linux2.l_i_blocks_hi = b >> 32;
45	} else if (b > 0xFFFFFFFF)
46		return EOVERFLOW;
47	inode->i_blocks = b & 0xFFFFFFFF;
48	return 0;
49}
50
51errcode_t ext2fs_iblk_sub_blocks(ext2_filsys fs, struct ext2_inode *inode,
52				 blk64_t num_blocks)
53{
54	unsigned long long b = inode->i_blocks;
55
56	if (!(fs->super->s_feature_ro_compat &
57	      EXT4_FEATURE_RO_COMPAT_HUGE_FILE) ||
58	    !(inode->i_flags & EXT4_HUGE_FILE_FL))
59	    num_blocks *= fs->blocksize / 512;
60
61	if (num_blocks > b)
62		return EOVERFLOW;
63
64	b -= num_blocks;
65
66	if (fs->super->s_feature_ro_compat &
67	    EXT4_FEATURE_RO_COMPAT_HUGE_FILE) {
68		b += ((long long) inode->osd2.linux2.l_i_blocks_hi) << 32;
69		inode->osd2.linux2.l_i_blocks_hi = b >> 32;
70	}
71	inode->i_blocks = b & 0xFFFFFFFF;
72	return 0;
73}
74
75errcode_t ext2fs_iblk_set(ext2_filsys fs, struct ext2_inode *inode, blk64_t b)
76{
77	if (!(fs->super->s_feature_ro_compat &
78	      EXT4_FEATURE_RO_COMPAT_HUGE_FILE) ||
79	    !(inode->i_flags & EXT4_HUGE_FILE_FL))
80		b *= fs->blocksize / 512;
81
82	inode->i_blocks = b & 0xFFFFFFFF;
83	if (fs->super->s_feature_ro_compat & EXT4_FEATURE_RO_COMPAT_HUGE_FILE)
84		inode->osd2.linux2.l_i_blocks_hi = b >> 32;
85	else if (b >> 32)
86		return EOVERFLOW;
87	return 0;
88}
89